Maker Pro
Maker Pro

divide-by-5 and divide-by-10?

K

Kay

Jan 1, 1970
0
Hi, All:

Is there any way to hook up a divide-by-5 and divide-by-10 counter using a
binary counter? I was using 74LS90 to do this before, but it stopped
working. I am now thinking to transfer to HCT family but I can't find any
decade/binary counter in HCT family, only binary counter is available, not
sure why.

thanks,
-Kay
 
R

R. Steve Walz

Jan 1, 1970
0
Kay said:
Hi, All:

Is there any way to hook up a divide-by-5 and divide-by-10 counter using a
binary counter? I was using 74LS90 to do this before, but it stopped
working. I am now thinking to transfer to HCT family but I can't find any
decade/binary counter in HCT family, only binary counter is available, not
sure why.

thanks,
-Kay
-----------
The only reason it "stopped working" is because the way YOU used it
blew it up, which you'll do with ANY counter handed to you. Instead
of looking for a different counter you should look for a different
designer, or improve your skills by finding out what you did wrong!

-Steve
 
M

Michael Black

Jan 1, 1970
0
Kay said:
Hi, All:

Is there any way to hook up a divide-by-5 and divide-by-10 counter using a
binary counter? I was using 74LS90 to do this before, but it stopped
working. I am now thinking to transfer to HCT family but I can't find any
decade/binary counter in HCT family, only binary counter is available, not
sure why.

thanks,
-Kay

I just pulled out a databook, and it shows there were (I have no
idea how available they still are) 74HC390s, which are dual decade
counters about the equivalent of two 7490s.

Decade counters are made up of binary counters with some sort of
feedback to reset them early, so look in one of Don Lancaster's cookbooks
and you're bound to see how it's done, or even look at the datasheet
for the 7490.

What you are doing defines the end results. In the old days,
7490s were pretty common, in two places. One was merely to divide
the input signal by ten, and you only needed divide by ten output.
Other times they'd be in counters of some sort, and you actually
needed the BCD outputs, to drive BCD to decimal or seven segment
decoders. I suspect if you only need to divide something by
ten, you have a lot more leeway than if you actually need BCD
output. For instance, there was a 74HC4017.

And I am just looking at an older Motorola databook. Likely
there are other possibilities, if one looks.

Michael
 
D

dan williams

Jan 1, 1970
0
Steve!

a little less blame, a little more help...

Kay, what ARE you hooking the '90 up to?

dan

R. Steve Walz said:
-----------
The only reason it "stopped working" is because the way YOU used it
blew it up, which you'll do with ANY counter handed to you. Instead
of looking for a different counter you should look for a different
designer, or improve your skills by finding out what you did wrong!

-Steve

--
Dan Williams, Owner
Electronic Device Services
(604) 741 8431
RR8 855 Oshea rd
Gibsons BC Canada
V0N 1V8
 
J

Joe McElvenney

Jan 1, 1970
0
Hi,

The 74HC390 is a dual x2 plus x5 counter (there probably is a
74HCT version as well.) I designed one into a divide by 5,000
chain just recently. Incidently, a good chip for dividing by
awkward numbers is the 74HCT40103 which can be preset for any
count from 2 to 255 and clocks up to around 20MHz.


Cheers - Joe
 
K

Kay

Jan 1, 1970
0
Thank you all for pointing out things...I am trying to synchronize 2
devices. I don't know their internal circuits. The only thing I know is that
they are both TTL compatible...74LS90 worked fine for us until recently it
stopped working. I am now on the west coast and only had very basic
electronics. The summer student who is working on this on the east coast
hasn't had any electronics yet. I've ordered more 74LS90 online but not sure
if they can arrive on time. We have some binary counters at hand (74LS93
(x2), 74LS05, 74LS04, 74HC163, 74HCT161E) that's why I want to use binary
counters to build a divide-by-5&divide-by-10 circuit. I just figured out how
74LS90 works last night. Now I need to see if I can adapt a binary counter
easily to that...That said, 74LS90 has very limited input voltage range.
I've had static shocks in the lab before so I thought we somehow burnt the
chip. That's why I want a more noise-endurable TTL-compatible family
now...Again, I don't have any electronics textbook at hand right now, and I
only had very basic electronics at school. So the questions I asked might
sound silly.

thanks again,
-Kay
 
D

Dennis

Jan 1, 1970
0
I've used the 7490. It works best as an even modulo type
of counter. It can be set as a divide by 5,or 3 , but
the duty cycle won't be exactly symmetrical. For me
that was important for my app, it may not be for yours.

good luck,

Dennis
 
D

dan williams

Jan 1, 1970
0
it almost sounds like your mixing families that dont want to be mixed...
go to the manufacturers sites and look at the input and output
threashold voltages for the chips your interfacing. you may need pull
up/down resistors.

dan

Thank you all for pointing out things...I am trying to synchronize 2
devices. I don't know their internal circuits. The only thing I know is that
they are both TTL compatible...74LS90 worked fine for us until recently it
stopped working. I am now on the west coast and only had very basic
electronics. The summer student who is working on this on the east coast
hasn't had any electronics yet. I've ordered more 74LS90 online but not sure
if they can arrive on time. We have some binary counters at hand (74LS93
(x2), 74LS05, 74LS04, 74HC163, 74HCT161E) that's why I want to use binary
counters to build a divide-by-5&divide-by-10 circuit. I just figured out how
74LS90 works last night. Now I need to see if I can adapt a binary counter
easily to that...That said, 74LS90 has very limited input voltage range.
I've had static shocks in the lab before so I thought we somehow burnt the
chip. That's why I want a more noise-endurable TTL-compatible family
now...Again, I don't have any electronics textbook at hand right now, and I
only had very basic electronics at school. So the questions I asked might
sound silly.

thanks again,
-Kay

--
Dan Williams, Owner
Electronic Device Services
(604) 741 8431
RR8 855 Oshea rd
Gibsons BC Canada
V0N 1V8
 
A

Active8

Jan 1, 1970
0
it almost sounds like your mixing families that dont want to be mixed...
go to the manufacturers sites and look at the input and output
threashold voltages for the chips your interfacing. you may need pull
up/down resistors.

dan

yeah. those HCs aren't going to agree with their TTL cousins. that's
what xCTs are for.

mike
 
F

Fred Bloggs

Jan 1, 1970
0
Kay said:
Thank you all for pointing out things...I am trying to synchronize 2
devices. I don't know their internal circuits. The only thing I know is that
they are both TTL compatible...74LS90 worked fine for us until recently it
stopped working. I am now on the west coast and only had very basic
electronics. The summer student who is working on this on the east coast
hasn't had any electronics yet. I've ordered more 74LS90 online but not sure
if they can arrive on time. We have some binary counters at hand (74LS93
(x2), 74LS05, 74LS04, 74HC163, 74HCT161E) that's why I want to use binary
counters to build a divide-by-5&divide-by-10 circuit. I just figured out how
74LS90 works last night. Now I need to see if I can adapt a binary counter
easily to that...That said, 74LS90 has very limited input voltage range.
I've had static shocks in the lab before so I thought we somehow burnt the
chip. That's why I want a more noise-endurable TTL-compatible family
now...Again, I don't have any electronics textbook at hand right now, and I
only had very basic electronics at school. So the questions I asked might
sound silly.

thanks again,
-Kay

If you have to use the LS93 and the LS05 is available then you can do
something like this:

Please view in a fixed-width font such as Courier.

DIVIDE BY 5

CLK>-----------------------+----------+
TTL | |
IN inverters --- ---
74LS05 \ / \ /
O O
| |
| |
| | 1k
CLK +------------/\/\---+-o Vcc
--- <-+ +--------+--+ | | |
5 | | | | | +--------------+
| | | | | | | |
| | +-RO-RO--CLK--CLK-+ | |
| | | 1 2 B A | | |
| | | | | |
| | | 74LS93 | | |
| | | | | |
| | +-QD--QC--QB---QA-+ | |
| | | | | | |
+---|-------|---+ +---|<|----+ |
| | '4148 | 680 |
| +-----------|<|----+--/\/\--+
| 1k | |
+-----------+--/\/\--------|--------+
| | | |
| | --+-- |
| | '3904 / \ |
| | +----+-e c-----+
| | | | |
o --- --- | 220 |
/ \ \ / \ / +--/\/\-o gnd |
--- O O |
| 1000p | | 1k |
+----||-----+----+------------/\/\--+
| |
| 680 |
+-----------------------------/\/\--+




DIVIDE BY 10

CLK>----------------------------+-----+
TTL | |
IN inverters --- ---
74LS05 \ / \ /
O O
| | 1k
CLK +-------/\/\---+-o Vcc
--- <-+ +--------+--+ | | |
10 | | | | +----|---------+ |
| | | | | | | | |
| | +-RO-RO--CLK--CLK-+ | | |
| | | 1 2 B A | | | |
| | | | | | |
| | | 74LS93 | | | |
| | | | | | |
| | +-QD--QC--QB---QA-+ | | |
| | | | | | | | |
| | | | | +---------+ |
| | | | | | |
+---|-------|---+ +---|<|----+ |
| | '4148 | 680 |
| +-----------|<|----+--/\/\--+
| 1k | |
+-----------+--/\/\--------|--------+
| | | |
| | --+-- |
| | '3904 / \ |
| | +----+-e c-----+
| | | | |
o --- --- | 220 |
/ \ \ / \ / +--/\/\-o gnd |
--- O O |
| 1000p | | 1k |
+----||-----+----+------------/\/\--+
| |
| 680 |
+-----------------------------/\/\--+



DIVIDE BY 5 AND 10

CLK>-----------------------+----------+
TTL | |
IN inverters --- ---
74LS05 \ / \ /
O O
| |
| |
| | 1k
+------------/\/\---+-o Vcc
+--------+--+ | | |
| | | | +--------------+
| | | | | | |
| +-RO-RO--CLK--CLK-+ | |
| | 1 2 B A | | |
| | | | |
| | 74LS93 | | |
| | | | |
| +-QD--QC--QB---QA-+ | |
| | | | | |
+---|-------|---+ +---|<|----+ |
| | | '4148 | 680 |
| | +-----------|<|----+--/\/\--+
| | 1k | |
| +-----------+--/\/\--------|--------+
| | | | |
| | | --+-- |
| | | '3904 / \ |
| | | +----+-e c-----+
| | | | | |
| o --- --- | 220 |
| / \ \ / \ / +--/\/\-o gnd |
| --- O O |
| | 1000p | | 1k |
| +----||-----+----+------------/\/\--+
--- | |
\ / | 680 |
O +-----------------------------/\/\--+
| |
| 1k |
+--------------------------+------/\/\--+
| |
| +-----+--+----+ |
| | | | | |
| | +-RO-RO--CLK--CLK-+
| --- | 1 2 B A |
| gnd | |
| | 74LS93 |
| | |
| +-QD--QC--QB---QA-+
| |
| |
\|/ \|/

CLK CLK
--- ---
5 10



DIVIDE BY 5 OR 10

CLK>----------------------------+-----+
TTL | |
IN inverters --- ---
74LS05 \ / \ /
O O
| | 1k
+--+-------/\/\---+-o Vcc
|5 | | |
SW o | | |
o | | |
CLK <-+ +--------+--+ |\o------------+ |
OUT | | | | | 10 | | | |
| | | | | | | | |
| | +-RO-RO--CLK--CLK-+ | | |
| | | 1 2 B A | | | |
| | | | | | |
| | | 74LS93 | | | |
| | | | | | |
| | +-QD--QC--QB---QA-+ | | |
| | | | | | | | |
| | | | | +---------+ |
| | | | | | |
+---|-------|---+ +---|<|----+ |
| | '4148 | 680 |
| +-----------|<|----+--/\/\--+
| 1k | |
+-----------+--/\/\--------|--------+
| | | |
| | --+-- |
| | '3904 / \ |
| | +----+-e c-----+
| | | | |
o --- --- | 220 |
/ \ \ / \ / +--/\/\-o gnd |
--- O O |
| 1000p | | 1k |
+----||-----+----+------------/\/\--+
| |
| 680 |
+-----------------------------/\/\--+
 
F

Fred Bloggs

Jan 1, 1970
0
Fred said:
If you have to use the LS93 and the LS05 is available then you can do
something like this:

Please view in a fixed-width font such as Courier.

DIVIDE BY 5

CLK>-----------------------+----------+
TTL | |
IN inverters --- ---
74LS05 \ / \ /
O O
| |
| |
| | 1k
CLK +------------/\/\---+-o Vcc
--- <-+ +--------+--+ | | |
5 | | | | | +--------------+
| | | | | | | |
| | +-RO-RO--CLK--CLK-+ | |
| | | 1 2 B A | | |
| | | | | |
| | | 74LS93 | | |
| | | | | |
| | +-QD--QC--QB---QA-+ | |
| | | | | | |
+---|-------|---+ +---|<|----+ |
| | '4148 | 680 |
| +-----------|<|----+--/\/\--+
| 1k | |
+-----------+--/\/\--------|--------+
| | | |
| | --+-- |
| | '3904 / \ |
| | +----+-e c-----+
| | | | |
o --- --- | 220 |
/ \ \ / \ / +--/\/\-o gnd |
--- O O |
| 1000p | | 1k |
+----||-----+----+------------/\/\--+
| |
| 680 |
+-----------------------------/\/\--+




DIVIDE BY 10

CLK>----------------------------+-----+
TTL | |
IN inverters --- ---
74LS05 \ / \ /
O O
| | 1k
CLK +-------/\/\---+-o Vcc
--- <-+ +--------+--+ | | |
10 | | | | +----|---------+ |
| | | | | | | | |
| | +-RO-RO--CLK--CLK-+ | | |
| | | 1 2 B A | | | |
| | | | | | |
| | | 74LS93 | | | |
| | | | | | |
| | +-QD--QC--QB---QA-+ | | |
| | | | | | | | |
| | | | | +---------+ |
| | | | | | |
+---|-------|---+ +---|<|----+ |
| | '4148 | 680 |
| +-----------|<|----+--/\/\--+
| 1k | |
+-----------+--/\/\--------|--------+
| | | |
| | --+-- |
| | '3904 / \ |
| | +----+-e c-----+
| | | | |
o --- --- | 220 |
/ \ \ / \ / +--/\/\-o gnd |
--- O O |
| 1000p | | 1k |
+----||-----+----+------------/\/\--+
| |
| 680 |
+-----------------------------/\/\--+



DIVIDE BY 5 AND 10

CLK>-----------------------+----------+
TTL | |
IN inverters --- ---
74LS05 \ / \ /
O O
| |
| |
| | 1k
+------------/\/\---+-o Vcc
+--------+--+ | | |
| | | | +--------------+
| | | | | | |
| +-RO-RO--CLK--CLK-+ | |
| | 1 2 B A | | |
| | | | |
| | 74LS93 | | |
| | | | |
| +-QD--QC--QB---QA-+ | |
| | | | | |
+---|-------|---+ +---|<|----+ |
| | | '4148 | 680 |
| | +-----------|<|----+--/\/\--+
| | 1k | |
| +-----------+--/\/\--------|--------+
| | | | |
| | | --+-- |
| | | '3904 / \ |
| | | +----+-e c-----+
| | | | | |
| o --- --- | 220 |
| / \ \ / \ / +--/\/\-o gnd |
| --- O O |
| | 1000p | | 1k |
| +----||-----+----+------------/\/\--+
--- | |
\ / | 680 |
O +-----------------------------/\/\--+
| |
| 1k |
+--------------------------+------/\/\--+
| |
| +-----+--+----+ |
| | | | | |
| | +-RO-RO--CLK--CLK-+
| --- | 1 2 B A |
| gnd | |
| | 74LS93 |
| | |
| +-QD--QC--QB---QA-+
| |
| |
\|/ \|/

CLK CLK
--- ---
5 10



DIVIDE BY 5 OR 10

CLK>----------------------------+-----+
TTL | |
IN inverters --- ---
74LS05 \ / \ /
O O
| | 1k
+--+-------/\/\---+-o Vcc
|5 | | |
SW o | | |
o | | |
CLK <-+ +--------+--+ |\o------------+ |
OUT | | | | | 10 | | | |
| | | | | | | | |
| | +-RO-RO--CLK--CLK-+ | | |
| | | 1 2 B A | | | |
| | | | | | |
| | | 74LS93 | | | |
| | | | | | |
| | +-QD--QC--QB---QA-+ | | |
| | | | | | | | |
| | | | | +---------+ |
| | | | | | |
+---|-------|---+ +---|<|----+ |
| | '4148 | 680 |
| +-----------|<|----+--/\/\--+
| 1k | |
+-----------+--/\/\--------|--------+
| | | |
| | --+-- |
| | '3904 / \ |
| | +----+-e c-----+
| | | | |
o --- --- | 220 |
/ \ \ / \ / +--/\/\-o gnd |
--- O O |
| 1000p | | 1k |
+----||-----+----+------------/\/\--+
| |
| 680 |
+-----------------------------/\/\--+

Revise that simultaneous divide by 10 and 5 like so to line up the edges:

Please view in a fixed-width font such as Courier.


DIVIDE BY 5 AND 10

CLK>-----------------------+----------+
TTL | |
IN inverters --- ---
74LS05 \ / \ /
O O
| |
| |
| | 1k
+------------/\/\---+-o Vcc
+--------+--+ | | |
| | | | +--------------+
| | | | | | |
| +-RO-RO--CLK--CLK-+ | |
| | 1 2 B A | | |
| | | | |
| | 74LS93 | | |
| | | | |
| +-QD--QC--QB---QA-+ | |
| | | | | |
+---|-------|---+ +---|<|----+ |
| | | '4148 | 680 |
| | +-----------|<|----+--/\/\--+
| | 1k | |
| +-----------+--/\/\--------|--------+
| | | | |
| | | --+-- |
| | | '3904 / \ |
| | | +----+-e c-----+
| | | | | |
| o --- --- | 220 |
| / \ \ / \ / +--/\/\-o gnd |
| --- O O |
| | 1000p | | 1k |
| +----||-----+----+------------/\/\--+
| | |
| | 680 |
| +-----------------------------/\/\--+
| |
| 1k |
+---|---------------------------------/\/\--+
| |
| +--------------------------+
| | |
| --- +-----+--+----+ |
| \ / | | | | |
| O | +-RO-RO--CLK--CLK-+
| | --- | 1 2 B A |
+---+ gnd | |
| | 74LS93 |
| | |
| +-QD--QC--QB---QA-+
| |
| |
\|/ \|/

CLK CLK
--- ---
5 10
 
Top